Fault displacement modelling using 3D vector fields
- 279 Downloads
In history matching and sensitivity analysis, flexibility in the structural modelling is of great importance. The ability to easily generate multiple realizations of the model will have impact both on the updating workflow in history matching and uncertainty studies based on Monte Carlo simulations. The main contribution to fault modelling by the work presented in this paper is a new algorithm for calculating a 3D displacement field applicable to a wide range of faults due to a flexible representation. This gives the possibility to apply this field to change the displacement and thereby moving horizons and fault lines. The fault is modelled by a parametric format where the fault has a reference plane defined by a centre point, dip and strike angles. The fault itself is represented as a surface defined by a function z = f(x,y), where x, y and z are coordinates local to the reference plane, with the z-axis being normal to the plane. The displacement associated with the fault outside the fault surface is described by a 3D vector field. The displacement on the fault surface can be found by identifying the intersection lines between horizons and the fault surface (fault lines), and using kriging techniques to fill in values at all points on the surface. Away from the fault surface the displacement field is defined by a monotonic decreasing function which ensures zero displacement at a specified distance from the fault. An algorithm is developed where the displacement can be increased or decreased according to user-defined parameters. This means that the whole displacement field is changed and points on horizons around the fault can be moved accordingly by applying the modified displacement field on them. The interaction between several faults influencing the same points is taken care of by truncation rules and the ordering of the faults. The method is demonstrated on a realistic synthetic case based on a real reservoir.
KeywordsFault modelling Fault displacement History matching Uncertainty analysis
Unable to display preview. Download preview PDF.
- 1.Barnett, J.A.M., Mortimer, J., Rippon, J.H., Walsh, J.J., Watterson, J.: Displacement geometry in the volume containing a single normal fault. Am. Assoc. Pet. Geol. Bull. 71(8), 925–937 (1987)Google Scholar
- 4.Caumon, G., Tertois, A.L., Zhang, L.: Elements for stochastic structural perturbation of stratigraphic models. EAGE Petroleum Geostatistics, Extended Abstracts, A02 (2007)Google Scholar
- 7.Goovaerts, P.: Geostatistics for Natural Resources Evaluation. Oxford University Press, pp. 125–184 (1997)Google Scholar
- 8.Hoffman, K.S., Neave, J.W.: The fused fault block approach to fault network modelling. In: Jolley, S.J., Barr. D., Walsh, J.J., Knipe, R.J. (eds.) Structurally Complex Reservoirs. Geological Society, London, Special Publication, vol. 292, pp. 75–87 (2007)Google Scholar
- 10.Hollund, K., Mostad, P., Nielsen, B.F., Holden, L., Gjerde, J., Contursi, M.G., McCann, A.J., Townsend, C., Sverdrup, E.: Havana - a fault modeling tool. In: Koestler, A.G., Hunsdale, R. (eds.) Hydrocarbon Seal Quantification. Norwegian Petroleum Society (NPF), Special Publications, vol. 11, pp. 157–171 (2002)Google Scholar
- 15.RMS 2010.1: User Guide. Roxar Software Solutions, Stavanger, Norway (2010)Google Scholar
- 16.Røe, P., Abrahamsen, P., Georgsen, F., Syversveen, A.R., Lia, O.: Flexible simulation of faults. In: SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September, SPE 134912 (2010)Google Scholar
- 17.Seiler, A., Rivenæs, J.C., Aanonsen, S.I., Evensen, G.: Structural uncertainty modelling and updating by production data integration. In: SPE/EAGE Reservoir Characterization and Simulation Conference, Abu Dhabi, UAE, 19–21 October, SPE 125352 (2009)Google Scholar
- 18.Seiler, A., Aanonsen, S.I., Evensen, G., Lia, O.: An elastic grid approach for fault uncertainty modelling and updating using the Ensemble Kalman filter. In: SPE Europec/EAGE Annual Conference and Exhibition, Barcelona, Spain, 14–17 June, SPE 130422-PP (2010)Google Scholar
- 20.Yielding, G., Freeman, B., Needham, D.T.: Quantitative fault seal prediction. Am. Assoc. Pet. Geol. Bull. 81(6), 897–917 (1997)Google Scholar